Waste water streams generated from various industries, such as the paper and pulp industry, the textile industry and the polymer industry, contain unacceptable amounts of dissolved or suspended impurities. Cationic coagulants and flocculants are extensively used as treating agents for such waste water.
Residual cationic species in a water stream can cause fouling and environmental problems. Also, cationic species pose problems for processes like filtration, ion exchange, and reverse osmosis units.
In oil fields, waste water treatment has to be carried out for removing oil-in-water (OIW) reverse emulsions. Oil molecules often create a strong background fluorescent signal and thus pose a hurdle to the detection of cationic species.
In some instances, fluorescent tracers are added to waste water along with the treating agent. However, adding fluorescent tracers with the treating agent can itself be a challenge as the tracer may alter the properties of the treating agent and can further increase the production cost. The presence of residual fluorescent tracers in the treated water can also cause environmental issues.